Any expedition to the deep ocean depths is incredibly expensive, and returns with a host of strange and terrifying new species.

Meet Promachoteuthis sulcus, a bizarre creature straight out of your nightmares. It's a species of promachoteuthid squid and only one specimen has been found to date. It was captured in the Southern Atlantic Ocean at a depth of in

Hatchetfish are deep-sea fish found in the Pacific, Atlantic, and Indian oceans. They use a form of bioillumination to mimic light intensity from the surface, effectively cloaking it from poor-sighted predators. Creepy, but cool.